Paiza 問題集「クラスの作成」 : https://paiza.jp/works/mondai/class_primer/class_primer__make_class

employee.rb

class Employee
  attr_reader :number, :name

  def initialize(number, name)
    @number = number.to_i
    @name = name.to_s
  end
end

employee_recorder.rb

class EmployeeRecorder
  attr_reader :employees

  def initialize
    @employees = []
  end

  def make(number, name)
    @employees << Employee.new(number, name)

    nil
  end

  def getnum(index)
    @employees.each.with_index(1) do |employee, i|
      return employee.number if index.to_i.eql?(i)
    end
  end

  def getname(index)
    @employees.each.with_index(1) do |employee, i|
      return employee.name if index.to_i.eql?(i)
    end
  end
end

main.rb

solver = Solver.new(Solver.read_input!)
puts solver.solve!

order_string_analyzer.rb

class OrderStringAnalyzer
  attr_reader :order_string, :employee_recorder

  def initialize(order_string)
    @order_string = order_string
    @employee_recorder = EmployeeRecorder.new
    @execution_histories = []
  end

  def read_and_execute!
    @execution_histories =
      order_string.lines.map do |line|
        command, *args = line.split

        employee_recorder.public_send(command, *args)
      end
    nil
  end

  def execution_histories
    @execution_histories.compact
  end
end

order_string_analyzer_spec.rb

describe OrderStringAnalyzer do
  describe '#read_and_execute!' do
    context 'order string pattern 1' do
      let(:order_string) do
        <<~ORDER_STRING.lines.map(&:strip).join("\n")
        make 10 nana
        getnum 1
        getname 1
        ORDER_STRING
      end

      it 'reads and executes the commands' do
        analyzer = OrderStringAnalyzer.new(order_string)
        analyzer.read_and_execute!

        expect(analyzer.employee_recorder.getnum(1)).to eq(10)
      end

      context 'when the command was done successfully' do
        it 'can read data from the execution histories' do
          analyzer = OrderStringAnalyzer.new(order_string)
          analyzer.read_and_execute!

          result = [10, 'nana']
          expect(analyzer.execution_histories).to eq(result)
        end
      end
    end

    context 'order string pattern 2' do
      let(:order_string) do
        <<~ORDER_STRING.lines.map(&:strip).join("\n")
        make 2742 mako
        getnum 1
        make 2782 taisei
        getname 2
        make 31 megumi
        getname 1
        getname 3
        ORDER_STRING
      end
      it 'reads and executes the commands' do
        analyzer = OrderStringAnalyzer.new(order_string)
        analyzer.read_and_execute!

        expect(analyzer.employee_recorder.getnum(1)).to eq(2742)
      end

      context 'when the command was done successfully' do
        it 'can read data from the execution histories' do
          analyzer = OrderStringAnalyzer.new(order_string)
          analyzer.read_and_execute!

          result = [2742, 'taisei', 'mako', 'megumi']
          expect(analyzer.execution_histories).to eq(result)
        end
      end
    end
  end
end

solver.rb

class Solver
  attr_accessor :order_string

  def initialize(order_string)
    @order_string = order_string
  end

  def solve!
    OrderStringAnalyzer.new(order_string)
      .tap { _1.read_and_execute! }
      .then { _1.execution_histories }
  end


  class << self
    def read_input!
      gets.to_i.times.map do
        gets.chomp
      end.join("\n")
    end
  end
end